Rotary piston internal combustion engine

ABSTRACT

In a rotary piston engine, anti-wear treatment such as metal spray, etc., is provided on a fixing surface of a center housing and side housings and particularly the fastening surface around the plug hole, in order to prevent abnormal wear of the fastening surface and the consequent disadvantage caused by abnormal wear.

' United States Patent [1 1 Fujiyama et al.

[451 Feb. l2, 1974 1 1 ROTARY PISTON INTERNAL COMBUSTION ENGINE 175]lnventors: Tetsuo Fujiyama; Takashi Hamamoto, both of Hiroshima, Japan[73] Assignee: Toyo Kogyo Co., Ltd., Hiroshima,

Japan [22] Filed: June 29, 1972 [21] Appl. No.: 267,263

[30] Foreign Application Priority Data June 29, 1971 Japan 46/56728 [52]US. Cl. 418/179, 418/61 [51] Int. Cl. F16m 1/04 [58] Field of Search418/61, 149, 178, 179

[56] References Cited UNITED STATES PATENTS 7 3,394,877 7/1968 Hantzcheet a1 418/178 X 3,359,953 12/1967 Groth 418/179 X 3,360,191 12/1967Yamamoto .1 418/178 X 3,575,537 4/1971 Yamamoto 418/178 X PrimaryExaminerC. J. Husar Assistant ExaminerLeonard Smith Attorney, Agent, orFirmSugruc, Rothwell, Mion, Zin'n and Macpeak fastening surface aroundthe plug hole, in order to prevent abnormal wear of the fasteningsurface and the' consequent disadvantage caused by abnormal wear.

7 Claims, 3 Drawing Figures ROTARY PISTON INTERNAL COMBUSTION ENGINEBACKGROUND OF THE INVENTION 1. Field of the Invention This inventionrelates to improvements in a rotary piston internal combustion engineconsisting of a center housing having a trochoidal inner surface andside housings disposed at both sides of the center housing, andespecially to the rotary piston internal combustion engine appliedanti-wear treatment on the fastening surfaces of the center housing andthe side housings.

2. Description of the Prior Art Generally, the basic structure of therotary piston engine requires that the inner faces of the side housingshave high dimensioned accuracy relative to each other and that coolantleakage from water jacket is securely prevented and therefore, the endface of each side housing and that of the center housing have beendirectly joined and firmly tightened with fastening bolts. Increasingtightness of application of torque to the fastening bolts is desirablefor the prevention of coolant leakage, but it causes an undesirable,abnormal wear of the center housing and the side housings. Namely, dueto the difference in thermal deformation resulting from rapid variationin' the temperature of the engine owing to the difference in the shapeand/or material of the side housings and the center housing, acorrelative slide has been produced on the fastening surface of the sidehousings and the center housing. Consequently, increasing tightness bytorque application through the fastening bolts has caused correlativeslide between the side housings and the center housing against anexcessive friction force on the fixing surface, which increases as aresult of abnormal wear of the fixing surface. Besides, abnormal wear ofthe fixing surface around the plug hole of the center housing isexceedingly increased because of expansion by pressures of compressionand explosion of air-fuel mixture, and by high temperatures around saidplug hole.

Therefore, due to said abnormal wear, high temperature gas may enter thespace between the fastening surface of theside housings and that of thecenter housing, thus causing premature deterioration of the ringslocated inwardly from the water jacket, which results in coolant leakagefrom the water jacket to considerably shorten the endurance of theengine.

SUMMARY OF THE INVENTION It is a purpose of this invention to applyanti-wear treatment such as metal spray etc., on the fastening surfaceof the center housing and the side housings of a rotary piston internalcombustion engine.

Further purposes and advantages of this invention will be apparent fromthe following description and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The drawings show two embodimentsrelated to this invention.

FIG. 3 is a front sectional view of a rotary piston internal combustionengine showing another embodiment of this invention.

DESCRIPTION OF PREFERRED EMBODIMENTS To explain an embodiment of thisinvention in accordance with the drawings, a casing 1 has a space 4formed by the center housing 2 made of aluminum material and the sidehousings 3 disposed at both sides of the center housing 2. The centerhousing 2 has a trochoidal sliding surface 5 formed by a chrome platedlayer 6. The side housings 3 are made of cast iron and those surfacesfastened to the end face of the center housing 2 are coated by a sprayedmetal layer 7 such as high carbon steel (0.8 percent carbon steel). Asantiwear treatment for the fastening surface, various means can beconsidered, but a metal spray is exceptionally effective because of itssimple procedure and superior self-lubrication. This anti-wear treatmentmay be effected on either the side housings or center housing, or

on both.

The center housing 2 and the side housings 3 are joined through saidspray layer 7 and are firmly tightened by fastening bolts 8. Waterpassages 9 and 10 form a water jacket and O ring indicated by 11. and 12seal the components.

FIG. 3 shows another embodiment of this invention with metal sprayedonly around the plug hole of the side housings within a 60 rotatingangle of eccentric shaft 13. At the fastening surface around the plughole, abnormal wear is effected by high temperature and high pressuresand is exceedingly increased. So, when the metal spray is treated on thefastening surface around the plug hole throughout at least a 60 rotatingangle of eccentric shaft 13, it effects the same as when the metal sprayis treated on all fastening surfaces. The nearer the fastening surfaceis to trochoidal sliding surface, the larger the abnormal wear.Accordingly, it is effective to provide the metal spray limited to along and narrow situation and in parallel with trochoidal slidingsurface 5.

This invention is constructed as mentioned above, and therefore, evenwhere correlative slide is producted due to thermal deformation at thefixing surfaces between the center housing 2 and the side housings 3,the wear at the fastening surface is considerably decreased to preventcoolant leakage owing to abnormal wear of the fastening surface.

What is claimed is:

1. In a rotary piston internal combustion engine comprising a centerhousing having a trochoidal inner surface, side housings disposed atboth sides of said center housing, fastening surfaces formed by mutuallycon- FIG. 1 is a vertical sectional view of a rotary piston,

tacting surface portions of said housings, a rotary piston rotatingplanetarily through an eccentric shaft in a casing composed ofsaid-center housing and said side housings, the improvement wherein:said fastening surfaces only of at least one of said housings areprovided with an anti-wear treatment.

2. A rotary piston internal combustion engine as claimed in claim 1,wherein anti-wear treatment is provided on at least said fasteningsurface only around the plug hole and extending over at least a 60rotating angle of the eccentric shaft.

3. A rotary piston internal combustion engine as claimed in claim 2,wherein; said anti-wear treatment comprises a metal spray.

6. A rotary piston internal combustion engine as claimed in claim 2,wherein: said anti-wear treatment is.provided over the completefastening surface of said center housing.

7. A rotary piston internal combustion engine as claimed in claim 6,wherein said anti-wear treatment is further provided on said sidehousings.

1. In a rotary piston internal combustion engine comprising a centerhousing having a trochoidal inner surface, side housings disposed atboth sides of said center housing, fastening surfaces formed by mutuallycontacting surface portions of said housings, a rotary piston rotatingplanetarily through an eccentric shaft in a casing composed of saidcenter housing and said side housings, the improvement wherein: saidfastening surfaces only of at least one of said housings are providedwith an anti-wear treatment.
 2. A rotary piston internal combustionengine as claimed in claim 1, wherein anti-wear treatment is provided onat least said fastening surface only around the plug hole and extendingover at least a 60* rotating angle of the eccentric shaft.
 3. A rotarypiston internal combustion engine as claimed in claim 2, wherein; saidanti-wear treatment comprises a metal spray.
 4. A rotary piston internalcombustion engine as claimed in claim 2, wherein: said anti-weartreatment is provided only on said fastening surface close to thecombustion chamber and extends in long and narrow fashion, parallel withthe trochoidal sliding surface.
 5. A rotary piston internal combustionengine as claimed in claim 4, wherein: said anti-wear treatment isprovided on said side housings.
 6. A rotary piston internal combustionengine as claimed in claim 2, wherein: said anti-wear treatment isprovided over the complete fastening surface of said center housing. 7.A rotary piston internal combustion engine as claimed in claim 6,wherein said anti-wear treatment is further provided on said sidehousings.